Loading mechanism for multi-platen hot-press



p 1 1970 I I SEIHO KAJI 3,531,003

I LOADING MECHANISM FOR MULTI-PLATEN HOT-PRESS Filed Sept. 16; 1968 v v 2 Sheets-Sheet 1 FIG! Seiho Kqji I N VENTOR.

BY 611, (1* v Attorney Sept. 29, 1970 SEIHO KAJI 3,531,003

LOADING MECHANISM FOR MULTI-PLATEN HOT-PRESS Filed'Sepc. 16, 1968 2 Sheets-Sheet 2 Seiho Kqji INVENTOR.

I A tto n xey United States Patent Ofice 3,531,003 Patented Sept. 29, 1970 US. Cl. 214-166 Claims ABSTRACT OF THE DISCLOSURE A system for the simultaneous charging of a multiplaten or multilevel press in which a'charging rack is disposed adjacent the input side of the press and is provided with a number of fixed trays corresponding to the number of platens of the press. Each of the fixed trays cooperates with a movable tray therebelow so that the movable tray has an abutment overlying the fixed tray whereby a sheet-like body to be compressed is deposited upon a stationary tray, is advanced into the press on the movable tray upon reciprocation thereof, and is pushed off the movable tray during its retraction by engagement of the trailing edge of the sheet with the leading-edge abutment of the stationa ry tray. The charging rack may itself be movable toward and away from the press so as to position the leading edges of the stationary plates at the desired locations with respect to the platens, thereby accurately locating the sheets within the press.

My present invention relates to a charging system for a multilevel heated-platen press and, more particularly, to an improved loading mechanism for a multiplaten hot press.

A number of press-charging systems have been proposed heretofore, these systems principally including a charging rack adjacent the multiplaten or multilevel press and having a number of stages each aligned with their corresponding platen. In general, these systems have made use of a conveyor bar or the like adapted to sweep the stationary supporting stages of the chargingrack and carry the sheet material to be compressed into the press; in an alternative system, the press-charging rack has a plurality of movable trays or stages which are advanced into the press while carrying the sheet material and are then withdrawn while fingers or the like alongside the charging rack swing into the path of the sheet paths and engage the trailing edges thereof as the charging tray is withdrawn. Thus, in the first case, the sheet rests upon a stationary charging surface and is advanced by a pusher mechanism independently of the sheet-supporting surface whereas, in the second case, the single sheet-supporting surface advances into the press to carry the sheet material into the latter. a

The term sheet material is used here to designate any of the crude slabs commonly subjected to hot pressing in a multilevel press; suchsheets may include the loosely coherent or preliminary pressed mats of cellulosic fiber with or without binder which are commonly used as the basis for pressed board, veneer or plywood stacks of thin wood layers to be bonded together, or laminates of other types.

The aforementioned systems have been found to be relatively complicated, incapable of perfect synchronization, unable to switch over conveniently from sheet materials of one size (e.g. 4' x 8) to another (e.g. 3' x '6'), and to have a significant tendency to break down at the high operating rates and temperatures.

It is, therefore, the principal object of my present invention to provide an improved but simplified system for the charging of a multiplaten press.

Another object of this invention is to provide a system for the charging of a multilevel heated-platen press that is capable of cycling at high rate, e.g. two-minute cycles for SO-stage plywood presses, without the danger of break down.

Still another object of the instant invention is the provision of a system for charging a multilevel press and accurately positioning the compressible sheet therein.

I have found that the foregoing objects can be attained effectively, conveniently and economically through the provision-of a charging rack adjacent the input side of a multilevel press and shiftable toward and away from the latter while being provided with a plurality of vertically spaced press-charging stages each associated with a respective platen of the press, the charging stages being coupled together for joint operation.

According to the present invention, each of the charging stages comprises a stationary (relative to the rack) support tray which, as noted hereinafter, may be slotted; the receiving surface of this tray underlies the receiving surface of a respective movable tray which may be made up of slats receivable between the bars constituting the stationary tray. The movable tray of each charging stage is substantially coextensive with the stationary tray and is provided with an abutment along the trailing edge of the movable tray (with respect to the direction of ad- Vance of the sheet into the press) so as to sweep the receiving surface of the stationary tray and advance the sheet therealong onto the press platen.'The reciprocating means can be a reversible chain drive or any other system for advancing and retracting the movable trays jointly.

An important feature of this invention resides in that the raw sheets are deposited upon the receiving surfaces of the stationary trays ahead of the abutments of the respective movable trays, the sheets being advanced over the leading edges of the stationary trays by the abutments carried by the movable trays upon forward movement of the latter. Inasmuch as the receiving surface of the movable tray extends beyond the leading edge of the corresponding stationary tray, the sheets are thus passed onto the movable trays and carried by the latter into the press and onto the corresponding platens as the trailing edge of each sheet passes over the leading edge of the stationary plate; the latter is constituted as a stop or abutment which retains the sheet in the press as the movable tray is retracted. Advantageously, the leading edge of the stationary plate is formed with downwardly extending projections which are received between the slats of the movable tray to prevent entry of the sheets or the layers thereof between the stationary and movable trays.

According to still another feature of this invention, the abutments of each stationary tray are formed from members projecting upwardly between the bars of the stationary tray. Consequently, an interlocking and interfitting relationship of the two trays is established at each of the charging levels.

Yet another feature of this invention involves the provision at the trailing sides of the stationary trays with ramp-like guides for the incoming sheet material which is lifted thereby over the abutments at the trailing edges of the movable trays.

The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a plan view, partly in diagrammatic form, of a press-changing system, according to the present invention, adjacent a multilevel heated platen press;

FIG. 2 is a diagrammatic view of a charging system according to the invention in elevation;

FIGS. 3a, 3b and 3c are diagrammatic elevational views representing successive positions of the system in operation.

In the drawing, I show a system for the charging of a multiplaten press P having press platens 18 in vertically spaced relationship, which system comprises two interrelating components generally designated at A and B in FIG. 2. Component A is an assembly of horizontal trays 1, each of which is composed of a plurality of bars secured together at the leading edge between member 1b and at the trailing edge by a member 1a so that the tray 1 is formed with a multiplicity of gaps 1d extending in the direction of advance (arrow C) of the sheet material into the press P. Each of the trays 1 is associated with a respective platen 18 of the press and has a receiving surface 1e (FIG. 3a) located slightly above the receiving surface 18a of the respective platen. A frame supports the stationary trays 1 on wheels 7 (FIG. 2), which enable the rack to be shifted toward the press as represented by the broken showing of the vertical posts 3 and 3' of the charging rack, and is represented by the arrow D in FIG. 1. The posts 3 and 3' are connected by cros-spieces 13 etc. to form the charging rack which is designated generally at 6.

The second unit B of this system is an assembly of movable trays 8 of a construction similar to that of the stationary trays, each movable tray being associated and interfitted with a respective stationary tray 1 as is shown in detail in FIGS. 1 and 3a-3e. The movable trays 8 are each constituted of a plurality of slats 8c defining a receiving surface 8d and connected at their leading edges by a bar 811 which is formed with a shoe 8b composed of brass and designated to prevent damage to the harder receiving surface 18a of the platen 18. Supports carry the movable trays 8 when the latter are retracted. At the trailing edge of each of the trays 8, I provide an abutment 8a which extends above the receiving surface 1e of the stationary trays 1 and thus fits between the bars 10 thereof in the channels 1d. The bars 1c thus are guided in openings or notches 11 formed in the member 8a. Similarly, the cro-sspieces 1b of each stationary tray 1 are provided with openings through which the slats 8c are guided, the member 1b serving to prevent passage of the compressible sheet or any layer thereof between the trays of each charging system.

At the leading edge of each stationary tray 1 there is provided an array of stop members 4 which serve to retain the sheet material after its transfer from a stationary tray to a movable tray and during the restraction of the movable tray. The downwardly projecting portions of member 1b, which are received between the slats 8c of the movable tray, have been designated at 5 while the face of the abutment 8a is represented at 9.

On the opposite sides of the charging rack, I provide a tray-recipricating assembly comprising a pair of endless chains 13 which pass around sprockets 12, the shafts 15 of which are supported by brackets 14 affixed to the upstanding posts 3 and 3'. The chain mechanism is reversibly driven by conventional motors not shown. At the right-hand sides of the movable tray 8, the latter are collectively secured by the vertical members 17 to the chains 13 which thus advance the movable tray in the direction of arrow C and can be reversed to retract these trays in the direction of arrow E..Reference numeral 19 designates the new layer of sheet material to be introduced into the press while numeral 20 designates the previously compressed sheet. At the input side of the charging station, tray 1 is provided with a ramp-like guide surface 21 adapted to guide the incoming sheet material over the member 8a of the respective movable tray. The stationary trays 1 are loaded in conventional manner, e.g. via an elevatable and lo'werable rack or the like.

In operation, while the press P is in the midst of a i 4 previous compression cycle, the sheet layers 19are fitted into the charging rack over the ramps 21 until they drop onto the receiving surfaces 1e of the respective charging levels ahead of the abutment surface 9 of member 8a. When the entire charging rack is loaded, the press P is opened and the rack 6 advanced on wheels 7 (arrow D) to position the leading edges of the stationary trays 1 and the abutments 4 at the desired location of the trailing edge of each sheet 19 on the platen 18.

The chain drive 13, etc. is then'operated to shift the movable trays 8 to the left (arrow C) whereby the leading edge 8b of the movable tray pushes the previously formed sheet 20 off the corresponding platen 18 (FIG. 2) while the abutment 8a, 9 pushes the new sheet 19 over the leading edge 4 of the stationary tray 1 and deposits the sheet upon the receiving surface 8d of the movable tray (FIG. 317). At this point, the movable tray 8 is located fully 'within the press and overlies the platen 18.

The chain drive 13, etc. is reversed (arrow E) to withdraw the surface 8d while the stops 4 engage the trailing edge of the sheets 19 (FIG. 30). The sheets 19 are thus stripped from the movable trays 8 and properly positioned upon the respective platens.

The aforedescribed system has proved to be particularly effective for the production of plywood and other sheets or plates in which multiplaten presses have been used heretofore. This system is inexpensive and its operation comparatively simple since the same system charges the press and also accurately positions the layers. It has been found that substantially any sheet material can be transferred in this manner, even if roughly prepared, Without the use of caul plates. While the stationary tray 1 has been shown to be located above the movable tray 8 at each charging station, it will be understood that the slats and bars 8c and 10 can be interleaved so that the two trays are coplanar.

The improvement described and illustrated is believed to admit of many modifications within the ability of persons skilled in the art, all such modifications being considered within the spirit and scope of the invention except as limited by the appended claims.

I claim:

1. A charging system for a multiplaten press having a multiplicity of vertically spaced platens, said system comprising a charging rack along an input side of said press having a multiplicity of press-charging levels each associated with a respective one of said platens, each of said levels including a first sheet-receiving tray fixedly positioned with reference to said rack and a second sheetreceiving tray shiftable relatively to the first tray and said rack into said press to overlie the associated platen, said second tray of each of said charging levels being formed with abutment means at a trailing edge thereof with reference to a direction of advance of said second tray into said press for entrainment of a sheet of compressible material deposited on the corresponding first tray over the leading edge of the corresponding first tray and onto said second tray, said leading edge of each first tray being formed with stop means engageable with the trailing edge of the respective sheet upon retraction of the corresponding second tray away from said press, thereby stripping the sheet from the second tray and depositing the sheet upon associated press platens; and means for jointly shifting the second trays of said charging levels toward and away from said press.

2. The system defined in claim 1, further comprising means for shifting said rack relatively to said press to position the leading edges of said first trays above the associated platens at the desired positions of the trailing edges of the sheets delivered to said press.

3. The system defined in claim 2 wherein said first tray at each of said charging levels is formed with a plurality of mutually spaced parallel bars extending in the direction of movement of the second trays and defining chan- 5 nels between them, said abutment means passing through said channels.

4. The system defined in claim 3 wherein the second tray of each of said charging levels is formed with a plurality of mutually spaced parallel slats defining channels extending in said direction between the slats, the corresponding first tray being formed with downwardly extending projections and its leading edge receivable in the channels between said slats.

5. The system defined in claim 4 wherein said means for shifting said second trays includes an endless chain mounted on said rack and a vertical member connected with said chain and with said second trays.

6. The system defined in claim 5, further comprising guide means along the trailing edge of each of said first trays for lifting an incoming sheet above said abutment means upon deposition of the sheets on the surface of said first trays. J

7. The system defined in claim 6 wherein the first and second trays of each charging level are substantially coplanar.

8. The system defined in claim 6 wherein the first and second trays of each charging level have sheet-receiving surfaces disposed one above the other, both of said surfaces being located above the receiving surface of the corresponding plate.

9. The system defined in claim 5 wherein said second tray of each of said charging levels is formed along its leading edge with means preventing marring of the receiving surface of the corresponding platen.

10. The system defined in claim 9 wherein the lastmentioned means includes at least one brass shoe.

References Cited UNITED STATES PATENTS 9/1967 Nagaoka 2l4l6.6 8/1968 Carlsson et al. 2l4l6.6 

